1. Field of the Invention
The present invention relates to positioning devices and more particularly to position devices which accurately position a conduit.
2. Description of the Prior Art
An integral part of a septic system is a field drain bed where the effluent is allowed to disperse over a wide area and be absorbed into the ground. Modern health department requirements in most governmental jurisdictions specify very tight limits on the geometry of a field drain bed. The field drain bed consists of a series of perforated conduits connected in parallel and laid in trenches with gravel or other granular material surrounding the conduits. One of the most critical parameters is the levelness of the conduits. It is common to require no more than a 2 inch variation in vertical position over the entire length of the conduits, usually about 100 feet. This is an especially daunting specification when one considers the circumstances under which the field drain bed is constructed. Usually the ground in which the trenches are formed is far from level. The trenches are cut out by a backhoe to a rough approximation. The conduit is laid throughout the trenches and then supported above the floor of the trench by a variety of devices. When the conduits are level, gravel or other granular material is dumped into the trench to support the conduits. U.S. Pat. No. 5,437,424 illustrates a device comprises of a vertical stake and right angle arms to support a conduit in a trench. When the conduit is at a desired level, gravel is place into the trench and the arms are rotated 90 degrees to enable the support assembly to be pulled out of the trench. The problem with this proposal is that it is very difficult to quickly drive the stake to a vertical position that measures up to the normal health department standards of levelness. U.S. Pat. Nos. 3,568,455, 4,043,139 and 5,242,247 go one step further by providing a vertically sliding element with support arms for more easily setting the vertical position. In each patent a set screw fixes the position. However, each of these prior art approaches fail to provide a means for accurately fixing the vertical position.